Silent operating multi-circuit push-pull switch



SILENT OPERATING MULTI-CIRCUIT PUSH-PULL SWITCH Filed Aug. 22, 1963 2Sheets-Sheet 1 FIGZZ INVENTORS PAUL H. m/vrm GUIVTHER s. GRIESHABERATTORNEYS United States Patent 3,253,111 SILENT OPERATING MULTI-CIRCUITPUSH-PULL SWITCH Paul H. Winter, Syracuse, and Gunther S. Grieshaber,Camillus, N.Y., assignors to Pass & Seymour, Inc., Syracuse, N.Y., acorporation of New York Filed Aug. 22, 1963, Ser. No. 303,751 12 Claims.(Cl. 200-167) This invention relates to multi-circuit switches and moreparticularly to such switches of the push-pull type suitable for use onpanels, dashes, cabinet fronts and the like.

It is a general object of the present invention to provide a novel andimproved type of push-pull, multi-cirouit switch having two circuitclosing positions each arranged to handle a pair of different circuits.

More particular-1y, it is an object of the invention to provide a switchof the push-pull type of extremely oompact and rugged constructionadapted for silent operation whereby it may be used in flight trainersand similar devices without giving any warning to student pilots that acondition change has been made.

An important object of the invention resides in the construction andarrangement of the component parts of the switch contributing to lowcost and facility of assembly, etc.

A particular feature of the invention resides in the manner of mountingthe stationary contacts whereby the terminals thereof are convenientlygrouped on the rear face of the switch housing to facilitate wiring,contact mounting and numbering.

Another important feature of the invention resides in the arrangement ofthe movable contact assembly and operator providing guidance, silencingand detent means to hold the switch in either of its two positions.

A further important feature resides in the mounting and circuitry for aknob housed lamp.

Other and further objects and features of the invention will be moreapparent to those skilled in the art upon a consideration of thefollowing specification and the accompanying drawings wherein isdisclosed a single, exemplary embodiment of the invention with theunderstanding that such changes and modifications may be made therein asfall within the scope of the appended claims without departing from thespirit of the invention.

In said drawings:

FIGURE 1 is an exploded side elevational view of the switch partially inlongitudinal central section;

FIGURE 2 is a side elevation thereof;

FIGURE 3 is a rear elevation thereof;

FIGURE 4 is a top plan view of the housing and its assembled stationarycontacts, with the cover and movable contact carrier removed;

FIGURE 5 is a vertical longitudinal section taken on line 55 of FIGURE4;

FIGURE 6 is a fragmentary longitudinal sectional view taken on brokenline 6-6 of FIGURE 5 and looking in the direction of the arrows;

FIGURE 7 is a side elevation of the assembled movable contact carrierand its stern;

FIGURE 8 is an end elevation of the assembly of FIGURE 7 looking fromthe left; and

FIGURE 9 is a schematic circuit diagram of the switch.

Panel mounted style switches for many uses have been of various types,rotary, oscillatin push, snap, etc., many of which are not satisfactoryfor specific applications. For instance, in certain types of flighttrainers using relatively low voltage direct current it had always beenconsidered necessary to use snap switches for operation by theinstructor to simulate and program various conditions to 3,253,111Patented May 24, 1966 "ice which the student pilot must make properresponses. It has been found nearly impossible to completely isolate theclick of the switches when operated, and as the noise served as awarning to the student pilot that something was about to happen, thetrainer manufacturers have been in quest of completely quiet push buttonswitches, but switch manufacturers have been unable to meet the demandbecause of the presumed need for a snap acting switch on direct currenteven on the low operating potential of twenty-eight volts.

It has now been demonstrated that a slow make and break switch isentirely adequate for this voltage and the switch about to be describedhas proved it in practice on aviation training devices requiring twocircuit, three-way switches.

Referring first to FIGURE 9 for a circuit arrangement for which thepresent switch is well adapted but to which it is by no meansrestricted, it will be seen that terminal 1 can be alternativelyconnected to terminals 3 or 2 by pushing or pulling on bridging member10 and that by simultaneously moving the other bridging member 11,terminal 4 can be connected to terminal 6 or terminal 5. Terminals 7 and8 are continuously connected to the handle housed lamp 12 independentlyof the position of the switch operator.

FIGURES 1 to 8 illustrate a panel mounted switch and its componentsconstructed in accordance with the present invention and comprising ahousing 15 of a suitable plastic insulating material molded to therectangular plan illustrated in FIGURES 1 to 3 having flat side walls 16of approximately square shape, elongated end walls 17, the open top 18and the closed bottom wall 20.

Arranged within the housing are a plurality of sets of stationarycontacts and a movable bridging contact for each set, the arrangement ofwhich is illustrated schematically in FIGURE 9 as explained above. Thenumhens in FIGURE 9 from 1 to 8, inclusive are representative ofterminals on the rear wall 20 of the housing as indicated in the circlesin FIGURE 3, which numbers are impressed on the insulating material foridentification purposes in wiring, except for the one numbered 8 whichis stamped on a metal strap as will appear hereinafter; As seen inFIGURE 9, although more may be used, there are two similar sets ofstationary contacts and bridging members. As shown in other figures oneset of stationary contacts is arranged along each end wall 17 of thehousing.

The movable contacts 10 and 11 are generally of U- shape and arestraddle mounted on a plastic carrier 21 best seen in FIGURES 7 and 8,and this is fitted with longitudinally directed ribs 2-2 on its outeredges adapted to be guided in longitudinal grooves 213 in the end walls17 of the housing, for reciprocation therein under the control of anoperating plunger 24 connected to the carrier as seen in FIGURES l and7. This plunger is hollow and formed of metal and insulated by a plasticsleeve 25 and is reciprocally mounted in a second insulating sleeve 26,best seen in the exploded view of FIGURE 1, having a reduced end whichis received in the mouth of a bore in the spigot 27 which acts as aguide therefor. The outer end of operating stem 24 is internallythreaded as seen at 28 to receive the threaded metal sleeve 29 aboutwhich is molded the translucent operating knob 29'.

The spigot 27 is secured by suitable means to the closure plate 30 ofsheet metal which closes the open end 18 of the housing 15 over aplastic cover 31, and is secured to the housing by means of integralstraps 32 extending a slight recess in this thickened wall.

the hooks snap over rounded protuberanices 36 to hold the cover inposition and the whole switch assembled.

The spigot 27 is used for mounting the switch in a panel such as 40appropriately drilled to receive it and is fitted with a pair of locknuts 41 and 42 as seen in FIGURES l and 2, which may be adjustable alongthe length of the spigot and appropriately spaced apart in accordancewith the thickness of the panel. A washer is arranged beneath each nutas shown, one of them having an extension with the downturned end 43which passes through a secondary lateral hole in the panel to preventthe washer from rotating. Although not shown this washer has an inwardlyprojecting lug received in a longitudinal groove on the outer surface ofspigot 27 to lock it also against rotation in respect to the panel.

FIGURE 6 shows in enlarged detail the connection of the respectiveexternal terminals 1 to 6, inclusive, to their internal contacts and thespecific terminal 3 in FIGURE 6 is connected with portion 44 within thehousing and resting against the bottom wall thereof. Intermediate 3 and44 is the shank 45 which passes through and closely engages the walls ofslot 46 in the bottom. wall 20 of the housing. The shank 45 is widerthan the terminal and has side lugs 47 which are partially severed bythe cuts shown and flared outwardly to engage over the outer surface ofwall 20 and lock the combined contact and terminal rigidly in positionin the housing. In a like manner all of the other terminals are securedin position and attached to their respective internal contacts, whichmay be of different shapes but nevertheless have some form ofenlargement which prevents them from being pulled through the rear wallby engaging its inner face.

The centrally disposed terminal 7, shown in FIGURE 3, is illustrated ingreater detail in FIGURE where it is seen to be substantially a piece ofmetal having a shank 50 which passes through a circular opening in thethickened outer portion of the rear wall 20 of the housing and has anintegral head 52 resting on the bottom of Where the shank 50 extendsoutside of the housing it is secured by a spring washer 51 and thenreduced in diameter to form the terminal 7 and transversely drilled at53 to receive a conductor. The shank 50 has an internal extension 55beyond the disc 52 which is in tubular form and is longitudinally splitto closely receive and electrically contact with the metal rod 56, seenin FIGURES 1 and 7, extending through a large portion of the operatingstem 24. This rod slides longitudinally within split sleeve 55 andmaintains electrical contact with terminal 7 irrespective of theposition of the operating stern. This also helps guide the operatingstem 24.

The terminal 8 differs from any of the previously described ones. Itcomprises a fiat metal strap 57, FIG- URES 2 and 3, secured against theouter surface of a side wall 16 of the housing, extending from itsinsulating cover 31 beyond its rear face to form the perforated terminal8 and is secured to the wall 16 by the pair of screws shown.

The terminal plate 57 closes the outer end of a bore through the sidewalls 16 beneath it, which slidably houses the detent 58 in the form ofa metal cup having the semi-spherical inner end. It is pressed inwardlyby helical spring 59 stressed between its bottom and the under surfaceof terminal plate 57, as seen in FIGURE 4, whereby the detent is pushedagainst the surface of metal sleeve 60 at the inward end of theoperating stem. This sleeve has the spaced grooves or channels 61therein to be engaged alternately by the detent to hold the operatingstem in either of its two alternate positions and to electricallyconnect it to the terminal 8.

As viewed in FIGURE 4 each side wall of the housing cup islongitudinally groove throughout its full length as at 62 and providedwith an undercut 63 whereby a flat terminal plate 64 may he slidlongitudinally in position therein from the open end, carrying with itits terminal plate, such as described in connection with 44 in FIGURE 6,and it is prevented from extending through the opening 46 for itsterminal plate by a transverse kink 56 bent therein and housed below theupper surface of bottom wall 20 in a depression 67 therein. It will benoted that the contact plates associated with similar terminals 1 and 4are diagonally opposite each other in the two side walls. Each contactplate 64 is of such length that it is continuously in contactwith one ofthe sliding springs on one of the movable contacts 10 or 11, and theother arm of that spring is arranged to alternately engage one of twocontacts in the oppositely facing longitudinally directed channel andsince each channel is equipped with similar pair of contacts but onewill be described. It will be noted that the channels 70 are as wide asthe distance between the undercuts 63 in the channels 62 and of the samedepth.

As viewed in FIGURE 5 the contact connected to terminal 2 has its mainshank portion 72 lying against the bottom of groove 70 and in alignmentwith terminal 2 on the outside of the housing. Near its inner end it isbent at right angles so as to form the extension 73 and again at rightangles to form the contact surface I portion 74 whose outer face isflush with the inner surface of the side wall 16.

A block of insulating material 75 is fitted against the shank 72 and theoffset 73 and extends for the full width of the slot 70. It is notchedout at 76 for the wing 77 which extends at right angles from theterminal shank 44, previously described, and is co-planar with 74 andthe outer face of the insulating material 75, as indicated by the dottedlineshowing its face in FIG- URE 5. In this wise one of the lobes of astraddle mounted bridging contact 10 or 11 can engage either 77 or 74dependent upon the position of the contactcarrier and its shank, whileits other arm continuously engages a straight contact such as 64,whereby the circuit of 1 or 4 is transferred to either 2 or 3 or 5 or 6,dependent upon which group of contacts is considered. It will be notedthat the actual contacting portion 77 is bent at right angles to theshank portion 44, as seen in FIGURE 4. It will be noted that theinsulation block 75 is held securely in position by being sandwichedbetween 72 and 77 on its faces and between 73 and the bottom wall 20 onits ends, and having its sides engaging the side walls of channel 70.

Because the double contacts are spaced closer to the center lines of thehousing than the individual contacts 64, the offset shape of the contactcarrier 21 as shown in FIGURE 8 is resorted to to properly dipose themovable contacts and it should be noted that they are secured to thecarrier respectively by hollow rivets 80 seen best in FIGURE 8. Each ofthe contacts 10 and 11 is generally U-shaped and straddles its side ofthe carrier closer to the stem thereof than the sliding members carryingthe keys 22. The arms of the contacts extend down over the sides of thecarrier 21 and each is provided with a struck out semi-spherical knob 82better to engage and slide over the stationary contacts and theinterposed insulation block 75.

Referring now to FIGURE 1 it will be seen that the carrier operatingstem 24 is hollow, formed of metal and has the tubular portion 60containing the detent receiving grooves 61. The lower end of thisportion fits over an extension on the contact carrier 21 and is securedthereto against relative rotation by the interlocking key 83 fitting inthe slot 84 in the portion 60, best seen in FIGURE 7. The centralconducting rod 56 passes through the carrier to secure it against thetubular portion 60 thereof, and a lock washer 85 prevents the extendingend from being drawn into the tube. At the opposite end the conductingrod 56 passes through an insulation washer 86, FIGURE 1, which is seatedat the bottom of the larger diameter internally threaded bore in theoperating shank, and there is fitted with a second lock washer 87insuring that the the miniature incandescent lamp 12, seen toward theleft of FIGURE 1, which is housed Within the tubular metal shank 29 ofthe plastic operating knob 29. The outer .contact 90 of the lamp has aflared upper end which engages the wall of the shank 29 of the operatingknob and connects the other terminal of the lamp to the thin metalsleeve which is threaded at 28 and surrounded by the insulating tubes25. This then places the lamp in circuit with the central contact 7 onthe end of the housing and the side contact plate 57 by way of thedetent 59 which engages the sleeve 60 and its lock channels 61.

In order that the switch be silent in operation a heavy rubber annulus91, FIGURES l, 4 and 5, surrounds the split sleeve 55 and is housed in arecess in the bottom wall of the housing and acts to stop inwardmovement of the operating sleeve and the carrier assembly in a noiselessmanner. Conversely the protruding ends 22' of the carrier keys 22sliding in the channels 23 in the end walls of the housing are silencedagainst rubber insets 92 set in notches in the upper edges of the endwalls of the housing, as seen in FIGURE 1, being held in diamond shapedrecesses therein 93, seen in FIGURE 4, and locked in position by theinsulating cover 31.

It will be noted that the switch has no snap action to make any sound,that the detent 59, spring-pressed in the grooves 61, is soundlessduring operation and motion of the carrier is stopped at either extremeof its travel by substantial rubber cushions so that the switch can wellbe said to be noiseless.

One of the moving contacts, for each of the two circuits controlled bythe switch, bears continuously on its stationary contact and no circuitsare broken thereby. The other movable contact breaks one circuit andmakes another whenever the position of the operator is changed, butduring such change the movable contacts pass over the insulation blocksand any slight arcs which follow the movable contacts breaking with thestationary contacts are quickly snuifed out, at the voltage of 28 usedin the circuit, by the relative coolness of the insulation block, itbeing understood that the circuits are not used often enough, nor dothey carry enough current to do any real heating of the insulationparts. Moreover, because of the detent mechanism, movement of thecontact carrier on breaking circuit is relatively rapid, since theoperator must pull or push on the knob with consider-ably more forcethan is necessary to normally move the stem and carrier, in order tobreak the detent out of its groove which results in a rapid movement ofthe handle and of the carrier so that the circuits are quickly openedsufficiently Wide to prevent arcing and by the same token are closedabout as quickly.

We claim:

1. In a switch of the type described, in combination: an insulatinghousing having a cavity formed by a closed bottom, four side walls, andan open top, a single contact extending longitudinally along one sidewall, a pair of separate contacts spaced longitudinally in alignmentalong an opposite side wall, a bridging contact adapted to selectivelyconnect either of said pair of contacts to said contact, an insulatingcarrier mounting said bridging contact, a conducting tube secured tosaid carrier, a cover closing said open top of said housing and having amounting sleeve secured to and extending therefrom normal to saidbottom, said tube being insulated from and guided in said sleeve forreciprocation and having an operating knob on the outer end thereof, andsupplemental means to guide said carrier independent of said contacts.

2. The switch of claim 1 in which said supplemental guide meanscomprises interfitting groove and tongue means on the carrier and an endwall of the housing.

3. The switch of claim 1 in which said knob is translucent, a lampcarried by said tube for illuminating said knob, a conductive rodsupported by and insulated from said tube and extending through thecarrier toward said housing bottom, a terminal on said bottom and havingsliding conductive engagement with said rod, means electricallyconnecting the lamp to the rod and tube, a second terminal on theoutside of said housing and means slidably and electrically connectingthe second terminal to said tube.

4. The switch of claim 3 in which said last mentioned means comprises aplunger spring pressed radially toward said tube, and spaced depressionsin said tube engageable by said plunger to retain said tube and carrierin each of two diiferent contacting positions.

5. The switch of claim 2 having a conductive rod coaxial and movablewith, supported by and insulated from said tube and extending throughsaid carrier toward said housing bottom, a split sleeve on said bottomreceiving and electrically contacting said rod and having a terminalextending through and beyond said bottom, and an external terminalelectrically connected to said tube whereby current may be continuouslysupplied to a device movable with and connected to said tube and rod.

6. The switch of claim 5 in which said device is an electric lamp, and atranslucent actuating knob secured to said tube and housing said lamp.

7. In a switch of the type described, in combination, an insulatinghousing of cup-like form having a pair of parallel walls, a singleelongated contact extending longitudinally along one of said walls, apair of contacts spaced longitudinally in alignment along the other wallopposite said first contact, an insulated contact carrier, a bridgingcontact secured to said carrier and having two oppositelydirectedspring-extended contacting areas positioned to slidably engage saidsingle and one or the other of said pair of contacts respectively,cooperating means on the housing and carrier for guiding the latterbetween and parallel to said contacts, terminals for said contactsextending through the cup bottom, a metal operating tube attached tosaid carrier, and a mounting spigot attached to said housing and havingguide means for said tube.

8. A switch as claimed in claim 7 in which said tube has spaced annulargrooves therein, a ball-tipped metal detent slidable in one of saidwalls, a spring urging said detent against said tube to selectivelyengage in said grooves to hold the tube, carrier and movable contact ineither of two operation positions.

9. The switch of claim 8 in which said tube is of metal, currentconsuming means carried by and connected to said tube, and a terminal onthe outside of said one wall electrically and mechanically engaging saidspring to conduct current to said tube.

10. The switch of claim 8 in which a conducting rod extends coaxiallywithin said tube, is connected to said current consuming means,insulated from the tube and extends beyond its end and through thecarrier, and a split tube and terminal mounted on the bottom of the cupand slidably engaging said rod.

11. The switch of claim 8 in which there is a resilient cushion at thebottom of said cup and another at the top for engagement by and to stopmovement of said contact carrier silently.

12. In a switch of the type described, in combination, an insulatinghousing of cup-like form having a pair of parallel walls, a singleelongated contact extending longitudinally along one of said walls, apair of contacts spaced longitudinally in alignment along the other wallopposite said first contact, an insulated contact carrier, a bridgingcontact secured to said carrier and having two oppositelydirectedspring-extended contacting areas positioned to slidably engage saidsingle and one or the other of said pair of contacts respectively, abottom wall on said housing, a channel extending longitudinally in oneof said parallel walls for its full length, a slot through said bottomwall having a wall common with said slot, one of said pair of contactscomprising a strap having a portion fitted in said slot against thebottom wall thereof, a terminal tab on said strap extending through saidslot and exposed 'outside said' bottom wall, the opposite end of saidstrap being offset to provide a fiat area for engagement by one of saidspring-extended contacting areas adjacent the inner face of saidparallel wall, the second of said pair of contacts having a flat areaspaced toward said housing bottom wall from and in the same plane as thefirst one, a lateral extension from said last mentioned flat areaengaging another wall of said housing and having a like terminal tabextending through the housing bottom wall, and a block of insulationengaging the inner face of the first strap below the offset therein tospace the second flat area therea flat face between and coplanar withsaid flat contacting areas to facilitate movement of the contact carrierand its contacting areas.

References Cited by the Examiner UNITED STATES PATENTS 3,126,507 3/1964Clem-inshaw 200-467 X FOREIGN PATENTS 1,297,295 3/ 1962 France.

KATHLEEN H. CLAFFY, Primary Examiner.

BERNARD A. GILHEANY, Examiner.

from, and said block of insulation having a portion with 15 HERMANJONES, Am'smm Examine!-

1. IN A SWITCH OF THE TYPE DESCRIBED, IN COMBINATION: AN INSULATINGHOUSING HAVING A CAVITY FORMED BY A CLOSED BOTTOM, FOUR SIDE WALLS, ANDAN OPEN TOP, A SINGLE CONTACT EXTENDING LONGITUDINALLY ALONG ONE SIDEWALL, A PAIR OF SEPARATE CONTACTS SPACE LONGITUDINALLY IN ALIGNMENTALONG AN OPPOSITE SIDE WALL, A BRIDGING CONTACT ADAPTED TO SELECTIVELYCONNECT EITHER OF SAID PAIR OF CONTACTS TO SAID CONTACT, AN INSULATINGCARRIER MOUNTING SAD BRIDGING CONTACT, A CONDUCTING TUBE SECURED TO SAIDCARRIER, A COVER CLOSING SAID OPEN TOP OF SAID HOUSING A MOUNTING SLEEVESECURED TO AND EXTENDING THEREFROM NORMAL TO SAID BOTTOM, SAID TUBEBEING INSULATED FROM AND GUIDED IN SAID SLEEVE FOR RECIPROCATION ANDHAVING AN OPERATING KNOB ON THE OUTER END THEREOF, AND SUPPLEMENTALMEANS TO GUIDE SAID CARRIER INDEPENDENT OF SAID CONTACTS.